Here's the letter Democrats just sent urging an investigation into Michael Flynn's ties to Russia Today

Top Democratic lawmakers are calling for an investigation into whether President Trump's National Security Adviser, Michael Flynn, violated the Constitution by being paid to speak at a gala in Moscow in 2015. Drew Angerer/Getty Images Top Democratic lawmakers are calling on the Defense Department to investigate whether President Donald Trump's national security adviser, Michael Flynn, ran afoul of the US Constitution by being paid to speak at a gala in Moscow celebrating the 10th anniversary of state-sponsored news agency Russia Today.

Democratic Reps. Elijah Cummings, Adam Smith, John Conyers, Jr., Bennie Thompson, Adam Schiff, and Eliot Engel wrote a letter to Secretary of Defense Jim Mattis on Wednesday requesting that the Defense Department "conduct a review of a potentially serious violation of the Emoluments Clause" of the Constitution by Flynn.

"Since his retirement in 2014, General Flynn has made regular appearances on Russia Today (RT), that country's state-sponsored propaganda outlet," the lawmakers wrote. "He has admitted to being paid on at least one of these occasions — at an RT gala in Moscow where he dined with Russian President Vladimir Putin."

Flynn told The Washington Post last year that he had been paid to speak at the event, but would not disclose the amount.

The Emoluments Clause deals with conflicts of interest that might arise by accepting gifts or payments from a foreign country. It has been cited by critics of President Trump's refusal to sell off his businesses, which operate in four continents and nearly two dozen countries.

"As a retired army officer, General Flynn was prohibited from accepting direct or indirect payments from foreign governments," the members wrote, citing the Defense Department's warning to military officers that they are still subject to the Emoluments Clause even after they retire.

The lawmakers pointed to a report released last month by the US intelligence community concluding that Russia Today, as part of Russia's "state-run propaganda machine," served as "a platform for Kremlin messaging to Russian and international audiences." The findings were contained in the community's report about Russia's attempt to influence the US election.

"We wrote this letter because the president chose as his top national security advisor someone who got paid to go have dinner with Vladimir Putin, right as the Russians were attacking our democracy," Rep. Elijah Cummings, ranking member on the House Oversight Committee, told Business Insider on Wednesday. "These are very serious constitutional concerns, and they deserve to be answered as soon as possible."

White House press secretary Sean Spicer, asked about the letter in a press briefing Wednesday, said "countless" former officers participated in the kind of speaking engagements Flynn did in Moscow for RT.

Rep. Elijah Cummings, D-Md., ranking member on the House Oversight Committee. AP

The declassified intelligence report about Russia's hacking campaign targeting US Democrats throughout the election devoted seven pages to Russia Today's "rapid expansion" in the US and around the world. It claimed the news agency had "positioned itself as a domestic US channel and has deliberately sought to obscure any legal ties to the Russian Government."

The Kremlin spends approximately $190 million a year on distributing RT programming, the report said, focusing on hotels and satellite, terrestrial, and cable broadcasting.

Flynn, who served as the director of the Defense Intelligence Agency from 2012 to 2014, suggested last year in an interview with The Washington Post that he saw no difference between RT, CNN, MSNBC, and Al Jazeera. He insisted that he had no media contract with RT.

"I have been asked by multiple organizations to be a [paid] contributor but I don't want to be," Flynn said at the time.

Flynn was investigated by counterintelligence officials last year for his repeated contact with Russia's ambassador to the US before Trump was sworn in, including at least one phone call on the day President Barack Obama imposed new sanctions on Russia for its election-related meddling.

In their letter, however, the Democratic congressmen honed in on Flynn's attendance at the RT gala.

"It is extremely concerning that General Flynn chose to accept payment for appearing at a gala hosted by the propaganda arm of the Russian government, which attacked the US in an effort to undermine our election," they wrote. "Even more concerning is that General Flynn ... may have violated the Constitution in the process."

The lawmakers requested that Mattis provide "all documents in the possession or control" of the DoD relating to Flynn's communications with Russian government officials, interactions with RT officials, and payments received from "any foreign source" from the time he retired through January 20, 2017.